__Objective__:

The objective of this experiment is to verify that *1
calorie = 4.186 joules*.

__Equipment__:

A calorimeter with electric heating element, a * dc* power source, two
multi-meters, a thermometer, a few connecting wires, water, a stop watch, and a
mass scale

__ __

__Theory__:

In the past several decades, it has been repeatedly verified by many scientists
and experimenters that when * 1 calorie of heat *is converted to

1cal = 4.18J.

** **

The heating element in a calorimeter may be connected to a power source for a
certain period during which electric work (energy) causes an increase in the
temperature of the fluid in the calorimeter**.** The result is the conversion of
electric work to heat energy**.** To calculate the energy delivered to the
calorimeter, the formula for **power** may
be used**:**

*P = W*/*t
or W = P
t .*

Since electric power is * P
= V I, *the above equation
that gives the electric energy consumption becomes

On one hand, by measuring the applied * voltage V*, the

Q_{total} = Q_{water} + Q_{Al} + Q_{brass
}.

or

Q_{total } = m_{w }c_{w} ΔT
+
m_{Al }c_{A}_{l} ΔT
+
m_{br }c_{br} ΔT.

Q_{total}= [ m_{w }c_{w
}+ m_{Al }c_{Al}
+ m_{br }c_{br} ]
ΔT.
(2)

This equation calculates the total heat generated in **calories** as
a result of electric work done in the heating element in **joules.**
Both values can be calculated in order **to determine the # of joules one calorie
can generate or vice versa.**

__ __

__Procedure__:

Using a zeroed mass scale, measure the mass of the internal container of the
calorimeter * m_{Al}* first, and then measure it again when it is

** Note **that the ammeter in this experiment is to measure a current that exceeds

Now that you have connected the calorimeter, the ammeter (* in +10A position*), and
the power source in series, it is

Now disconnect the ammeter from the power source for the purpose of first
selecting an operating voltage**.** Turn on the power source, and set the voltage
to not more than ** 6V. ** Turn off the power (without changing the voltage
setting), and reconnect the ammeter to the power source

It is better to write down the values of * V and I every 30 seconds*,
and then calculate a mean value for each, and use those mean values in the
calculation of consumed electric energy

t
(sec) |
10 |
20 |
30 |
40 |
50 |
60 |
.... |
.... |
.... |
.... |

I (Amps) |
||||||||||

V(volts) |

It is a good idea to keep shaking the calorimeter gently (or stirring the
water), once every minute to facilitate heat distribution**.** After the desired
period of heating is reached, turn off the power source and wait for the
temperature to reach its maximum**.** Record this maximum as **T _{f
}.**

__ __

__Data__:

__Given: __

**c _{w} =
1.000 cal **

** c _{Br} =
0.0924 cal /(gr
^{o}C)**

** c _{Al} =
0.215 cal /(gr
^{o}C)**

** t = 10.00 minutes
**as an example**.**

**(W/Q) _{accepted}**

__Measured:__* m_{w} ,
m_{br} , m_{Al} ,
T_{i }, T_{f} , V , I,
*and

__Calculations__:

Use equations * (1) and (2)* to calculate

__Comparison of the
Results__:

The accepted and measured values of **( W/Q)** may
be used to obtain a percent error

**
Conclusion:**

__
Discussion__: To be explained by students**.**